Junk shot



Jan. 16, 1962 .1. H. KIRBY u 3,016,830

JUNK SHOT Original Filed Nov. 25, 1955 United tates Patent @hhs Y3,016,830 Patented Jan. Y16, 1952 tmb Continuation of application Ser.No. 548,878, Nov. 25, 1955. This application Mar. 4, 1959, Ser. No.

6 Claims. (Cl. 162-20) This invention pertains to a device for breakingup material in a well bore that is interfering with the progress ofVdrilling the well, such material being commonly referred to as junkf lThis application is a continuation of my prior application of the samename, Serial Number 548,878, tiled November 25, 1955.

The object of the invention is to provide a simple and eicient devicefor breaking up junk.

A further object of the invention is to provide such a device that caneasily be brought into position adjacent the junk where it will beeffective to break it up.

According to the invention, an explosive charge is connected to thelower end of a string of pipe, lowered into the well, and with the aidof fluid jets from the lower` end of the pipe adjacent the charge thelatter is enabled to penetrate through the usual pile of cuttings anddetritus at the bottom of the hole until it contacts the junk at thelbottom of the hole. The charge is then detonated by means of an electricgo-devil lowered inside the pipe on a wire line. 'f

A further object of the invention is to protect the jets and detonationmeans as much as possible from the effect of the explosion of the chargewhereby these parts of the apparatus can be used again.

Other objects and advantages of the invention will appear from thefollowing description" of a preferred embodiment thereof, referencebeing made to the accom- Vpanying drawings wherein:

FIGURE 1 is an axial section through the tool and the bottom of a wellbore; and v FIGURE 2 is'an elevation, `partly in section, showing anignition device used with the-tool.

Referring to FIGURE 1, there is shown the lower end of a well bore witha piece of junk such as a lost of broken drill bit 11 at the bottom ofthe bore. Within the well bore is a stringof pipe 12 whose lower end isprovidedV with a threaded socket or tool joint 13 which may be integralwith the pipe as shown. A drill collar 14 is screwed into the tooljoint. In the lower end of the drill collar is screwed a tubulariringsub 15 which is of drill collar diameter. Y l

A plurality of electrically conducting leaf springs v16 are screwed to aconducting ring 17 -which is set in a recess 18 in the threaded pin 19of the upper end of the tiring ysub 15 and secured thereto by athreaded-pin 2 0. Near the lower end of the sub 15 there are a pluralityof downwardly directed passages 21. v sub has a slight inturned iiangeor shoulder 22. To the lower end of the tiring sub is connected a steelbumper sub 30 having an internally threaded socket 31.v The upper end ofthe bumper sub j3i) abuts against the lower end of firing sub 15 and isprovided with a tubular pin 32 which extends up into the lower part oftiring sub 15. A lock washer 33 is disposed around pin 32 and rests onshoulder 22 of the firing sub. A nut 34 is screwed to the threadedexterior of the upper end of pin 32 and rests on lock 'washer 33. Bythis means the bumper sub is held to the tiring sub. i

The bumper sub has a slightly smaller outer diameter than the outerdiameter of the tiring sub. Thelower end of the tiring sub is bevelledat.35 where the passages 21 ,terminate and the upper part of the bumpersub .is bevelled The bottom of the firingv at 36. In this manner thepassages 21 are directed downwardly as much as possible without theirdirection intersecting the bumper sub while still providing a bumper subof large outer diameter to hold the explosive charge next to bedescribed.

A charge housing 40 made of aluminum or other readily combustible orfrangible material has an outer diameter equal to that of the bumpersub. The upper end of charge housing 40 has a threaded pin 41 which tsinto socket 31 in the lower end of the bumper sub. Inside the chargehousing 40 is disposed an explosive charge 42 having a conical lower end43 which shape directs downwardly a large proportion of the eiect ofexplosion of the charge. The charge is retained within the housing 40 bymeans of an aluminum plug 44 held to the lower end of the housing byscrews 45. The lower face of plug 44 is tapered to a point 46 tofacilitate penetration to the bottom of the well bore.

An electric tiring cap 5l) is disposed adjacent the upper end of charge42, being disposed in passage 51 in pin 41. One electric contact at theupper end of the cap is soldered to the lower end of an electricallyconducting brass rod 52 whose upper end is screwed into a steel point 53forming an electric contact means. Around the rod 572 is an electricallyinsulating sleeve 54 disposed inside a steel tube 55. The latter extendsthrough passage 51 and pin 32 up into the firing sub 15. There is ailange 56 on tube 55 which rests against the bottom of a counterbore 57in the bumper sub 30 and is held thereagainst by the upper end of pin41. An O-ring 58 seals between tube 55 and passage 51. A wire 59 issoldered to tube 55 and the other electric contact of electric tiringcap 50.

Referring now to FIGURE 2, there is shown a tiring device adapted to belowered on a wire line 70 into the chamber 71 inside the tiring sub 15to set ott charge 42. Thering device comprises a rope socket 72connecting ythe wire line to a lishing neck 73 which is screwed intotheV top of a go devil or sinker bar 74. There are a plurality ofelectrically conducting belly springs 75 secured to the outside of thesinker bar which serve both to ground the firing device to the tiringsub and to center the tiring device in its passage down the drill pipeinto the firing sub. v

The lower end of the sinker bar is screwed into the top end of tubularbattery chamber 76 in which is disposed an electrically insulatingsleeve 77 and a plurality of dry cells 78 disposed with vtheir .contactpins 79 extending down. The dry cellsA are supported at their lower endby electrically insulating bushing 80 secured into the lower end ofchamber 76 and a contact pin 81 screwed into bushing 80 and engagingcontact pin 79 of the lowerrnost dry cell. Electrically conductingcompression spring 82 disposed between the top of the uppermost dry celland the pin on the lower end of the sinker bar keeps the dry cells yincontact with each other and connects the metal bottom formingone contactof the toprnost cell to the sinker bar and battery chamber.

to the ring sub, thereby closing acircuit from the dry cells through theelectric tiring cap 56 to set ofcharge 42. The explosion breaks up junk11 into small frag-V ments which can be recovered with conventionalfishing tools,I such as a permanent-magnet shing tool. The explosionalso destroys aluminum housing 441 which is i powdered or vaporized soas to leave no additional junk in the well bore. The bumper sub isdeformed so as not to be reuseable but will usually be retained on thelower end f the firing sub so that it can be easily retrieved. Thebumper sub acts as a shock absorber to protect the firing sub so that itis undamaged and can be reusedln While a preferred embodiment of theinvention has been shown and described, many modifications thereofcan'be made by one skilled in the art without departing from the spiritof the invention and it is desired to protect by Letters Patent allforms of the invention falling. within the scope of the followingclaims.

I claim:

l. A tool adapted to be run on the end of a string' of l pipe forbreaking up junkin a' well bore comprising a `charge housing meansreadily disintegrated by the explosion of the contained chargecontaining an explosive charge shaped to direct the force ofitsexplosion downwardly, said housing being closed at both ends exceptfor a passageway through the upper end thereof, a bumper sub means thatwill integrally survive an explosion and having an outer' diameter aslarge asthe' charge housing means connected to the upper end of the'Vcharge housing means and shielding the upper parts of the tool from theeffects of explosion of the charge, said bumper sub being of short axiallengthcompared to said charge housing means, said bumper sub having apassageway therethrough connecting with said passageway in the upper endof said charge housing means, means in said passageways for setting offsaid charge including an electric conductor extending upwardly from theupper end of said` bumper sub and an electric detonator having oneterminal connected to said conductor and the other terminal grounded, afiring sub connected to said bumper sub, said firing sub having an axialpassage therein open at its upper end, the lower end of said passagebeing' closed by said bumper sub and receiving the upper end of saidVelectric conductor, said firing sub having a plurality of azimuthallyspaced apart elongated passages each connected to said axial passage atone end and extending downwardly and outwardly at an acute angle to theaxis of the firing sub and opening to the outside of the tool just aboveand radially clear of the upper end of the bumper sub, means carried bythe firing sub for grounding an electric go-devil received in the firingsub, and means for connectingv the upper end of the firing sub to astring of pipe, whereby' the to'ol can be brought into effectiveposition adjacent a target in the bottom of a hole by the combinedaction of the weight of the string of pipe and the action of fluid underpressure passing down through the pipe string and out through saidazimuthally spaced apart passages in the firing sub immediately abovethe bumper sub and charge housing v means and said chargefcan then beexploded to act on the target following which the firing sub and bumpersub. can be withdrawn and the bumper sub removed and the remainder ofthe tool reused.V

2, A tool adapted to be run on the end of a string of pipe for breakingup junk in a well bore comprising a tubular charge housingmeans havingupper and'lower ends and including means closing the upper and lowerends thereof, an explosive Vcharge disposed in said housing and shapedto direct the blast of its explosion downwardly, and means connectedto's'aid charge' housing means for connecting said charge housing means'to such astring of pipe and including downwardly directed fluid 'passagemeans for' conveying fluid from said pipe tothe outside of said chargehousing means and for directing 'such fluid downwardly along the outsideof said housingl means, the passage formed between said tubular housingmeans' and the well bore that exists when the tool is run into a wellbore conveying the fluid to the region beneath said housing means tovwash detritus away fromjunk in the welll -bore beneath the tool andenable'the explosive charge to be positioned closely thereabove wherebythe downward blast of the explosion of the 'charge will act directly onlthe junk, and means for setting od the explosion of said charge, saidtool being further characterized by the fact that the means forconnecting the charge housing means to the string of pipe and includingdownwardly directed fluid passage means includes a drill collar adaptedto be connected to the lower end of the string of pipe and a tubularfiring sub connected to the lower end of the drill collar having thesame inner and outer diameters as the drill collar providing a thickwall in the lower part of which are disposed said downwardly directedfluid passage means and providing a central chamber adapted to receivean electric go-devil of the largest diameter that will pass through saiddrill collar after said go-devil has downwardly traversed the interiorof the string of pipe Vto'which the tool is connected, the means forsetting off an explosion of said charge including resilient electriclcontact means around the upper part of said central charnber of Asaidsub and extendingy inwardly therefrom to .en-I gage the go-devil, lsaidtool being further characterized by the fact that the charge housingmeans is made of readily destructible' material that is reduced by theexplosion of the charge toa form compatible with continued drilling inthe well bore and in which there isinterposed between the charge housingmeans and the firing sub a bumper means of durable material that willsurvivev the explosion of thecharge, said bumper means being of shortaxial extent compared to the length of said tubular charge housingmeans, the said fluid passage means in the lower part of the firing subterminating at the lower end of the firing sub where it engages saidbumper means, the' outer'diameter of the bumper means being less thanthat of said firing sub, the bumper means being substantallyclear of thepath of fluid emerging from said fluid passages in the firing sub, theouter diameter of said bumper means being as large as that of saidcharge housing' meansto protect the firing sub from explosion of saidcharge.

3. A tool adapted to be run on a string of pipe for breaking up; junk ina` well bore comprising housing means for containingV an explosivecharge and disintegrati'ngjfully after' the explosion of said charge,bumper means connected to one end of said housing means made of materialsuch that the bumper means survivesv explosion of such charge, fluiddischarge means connected to said bumper means ony the opposite sidethereof from said charge housing means, said bumper means being' of kaslarge a diameter as said charge housing means and serving as abufferbetween said fluid discharge means and said charge housing means, anexplosive charge disposed' in said housing means, said charge beingshaped to concentrate the blast of its explosion in a direction awayfrom 'said bumper means, said` fluid discharge means being connectableto said pipe to convey fluid from the interior of the pipe to theexterior of the tool and including passage means directing fluid pastsaid bumper means toward said charge housing means in the same generalldirection as the blast from explosion of said charge, whereby junk inthe well berel can be cleared of detritus by fluidforced down saidstring of pipe and through said fluid discharge means and the chargehousing means positioned closely VadjacentV the junk with the shapedcharge directed thereagainst, and means for set-V tingV off an explosionofl said charge, said meansfor setting off an explosion of the chargeincluding means forming a passage through'the end of saidl chargehousing means adjacent said bumper means and thence through said bumpermeans into an interior space in said fluid discharge means', anelongated unit disposed in said pas'- Vin said fluid discharge means toprovide at its end an "v 'electric contact, the outermost of saidYconcentric con ductors having a ange thereon held between and inelectrical contact with said bumper means and said end of said chargehousing means, said uid discharge means and Ibumper means being made ofelectrically conductive material, and resilient electrical conductormeans around the interior of said space in said fluid discharge meansproviding an electrical contact positioned farther from said bumpermeans than said electrical contact provided by the end of said innermostconductor, said interior space in said uid dischargemeans opening at theend thereof farther from said bumper means to communicate with theinterior of the pipe on which the too=l is run, whereby an electricgo-devil can be dropped throughsaid pipe into said space to engage saidcontacts and set od an explosion of said charge.

4. A tool adapted to be run on the end of a string of pipe for breakingup junk in a well bore comprising a charge housing means readilydisintegrated by the explosion of the contained charge containing anexplosive charge shaped to direct the force of its explosion downwardly,said housing means being closed at both ends except for a passagewaythrough the upper end thereof, an electrically actuated detonatordisposed in said passageway close to the upper portion of said explosivecharge, a bumper sub that will integrally survive an explosion andhaving an outer diameter as large as the charge housing means connectedto the upper end of the charge housing means and shielding the upperparts of the tool from the eiects of explosion of the charge, saidbumper sub being of short axial length compared to said charge housingmeans, said bumper sub having a passageway therethrough connecting withsaid passageway in the upper end of said charge housing means, a i'lringsub connected to said bumper sub, said firing sub having an axialpassage therein open at its upper end for the entrance of well uid andto receive an electric godevil, the lower end of said passage beingclosed by said bumper sub except for said passageway through said bumpersub which terminates at its upper end inside said axial passage in saidtiring sub, said firing sub having a plurality of azimuthally spacedapart elongated passages each connectedrto said axial passage at one endand extending downwardly and outwardly at an acute angle to the axis ofthe firing sub and opening to the outside of the tool just above andradially clear of the upper end of the bumper sub, electric conductingmeans connected to said detonator and extending through said passagewaysin the charge housing and bumper sub into said axial passage in saidtiring sub, said electric conducting means terminating at its upper endin electric con- Y' tact means for engagement with said electricgo-devil, and means for connecting the upper end of the tiring sub to -astring of pipe, whereby the tool can be brought into effective positionadjacent a target inthe bottom of a hole by the combined actionV of theweight of the string of pipe and the action of Huid under pressurepassing down through the pipe string and out'through said azi-V muthallyspaced apart passages in the tiring sub immediately` above the bumpersub and charge housing means and said charge can then be exploded to acton the target following which the firing sub and bumper sub can bewithdrawn and the bumper `sub removed andthe remainder of the toolreused. v j

5. In a tool adapted to be run in a well on a string of pipe comprisinga hollow charge housing made of material that will be'reduced by anexplosion to a drillable state and containing an explosive charge shapedto direct the main blast of its explosion downwardly ytoward the wellbottom, said housing further'containing a detonator for said explosivecharge, means for connecting the charge housing to the string of pipe,said connecting means having a fluid passage therethrough communicatingat its upper end with the interior of the pipe and atits lower end bymeans of a downwardly directed portion with the space exterior of thetool forming the annulus between the tool and well when the tool is inthe well whereby uid can be circulated down inside the pipe through thetool into the annulus, said connecting means including a firing subadapted to contain an electric power means, electric contact means insaid iiring sub, and means electrically connecting said contact means tosaid detonator, the improvement according to which said iring sub isopen at the top to receive said electric power means as part of anelectric ,go-devil run in through said pipe, said downwardly directedportion of the fluid passage is elongated and extends from the interiorof said tiring sub all the way to the exterior of tbe tool to form theuid leaving said passage into a jet stream directed downwardly towardthe well bottom, the distance between the lower end of said portion andthe upper end of said explosive is short compared to the length of saidcharge, the distance between the bottom of said charge and the lower endof said chargerhousing is short compared to the length of said charge,and said connecting means further includes a shielding means provided bya bumper sub of as large transverse dimensions as the charge housing,said shielding means being connected between said charge housing andsaid firing sub, said means electrically connecting said contact meansto said detonator means extending through said bumper sub, said bumpersub being of short length compared to the length of said charge.

6. A tool adapted to be run on the lower end of a string of pipe forbreaking up junk in a well bore comprising:

sub means for connecting the tool to the string of pipe and providingfluid passage means communieating with the interior of the pipe andincluding an elongated downwardly directed restricted portioncommunicating at the lower end of the sub means with the space exteriorof the tool that forms the annulus between the tool and well wall whenthe tool is in the well for forming iiuid leaving said elongated portioninto a downwardly directed jet stream,

charge housing means disposed below said sub means and containing anexplosive charge shaped to direct the force of the explosion downwardlyand disposed with the bottom of the charge adjacent the bottom of saidhousing means and the top end of the charge adjacent the top of saidhousing means, Y p said housing means also containing a detonator andbeing closed at both ends except for: a passage through'the upper endleading to the detonator and being made of material readilydisintegrated by the detonationof the contained charge, and

a bumper sub connected to and interposed between Y the top of saidcharge housing means and the bottom of said connecting sub means andmade ofmaterial that will integrally survive an explosion and having avertical extent that is short compared to the vertical extent of saidcharge placing the lower end of said jet forming portion of the fluidpassage means close to the charge housing means and having horizontaldimensions inall directions as large as said charge housing means toshield the portion of the tool thereabove from the effects of thedetonation of the charge.

